This research proposal is concerned with a study of carbohydrate-binding proteins of plant and animal origin. We are involved in the isolation, purification and characterization of a class of carbohydrate-binding proteins from plant seeds known as lectins or phytohemagglutinins. These (glyco)proteins are being used as probes for investigating the distribution and structure of complex carbohydrates (glycolipids and glycoproteins) present at cell surfaces and as reagents for distinguishing between certain types of normal and neoplastic cells. Our efforts are being directed toward the physical and chemical characterization of lectins, ascertaining their carbohydrate-binding specificity and quantitating their binding to animal cells. We also prepare immune antibodies against carbohydrate determinants. The antibodies are used to identify specific carbohydrate residues in complex carbohydrates, in solution and on cell surfaces.